1. What are the auscultatory areas of murmurs?
Auscultation typically starts in the aortic area, continuing in clockwise fashion: first over the pulmonic, then the mitral (or apical), and finally the tricuspid areas. Because murmurs may radiate widely, they often become audible in areas outside those historically assigned to them. Hence, ‘‘inching’’ the stethoscope (i.e., slowly dragging it from site to site) can be the best way to avoid missing important findings.
2. What is the Levine system for grading the intensity of murmurs?
The intensity or loudness of a murmur is traditionally graded by the Levine system (no relation to this book’s editor) from 1/6 to 6/6. Everything else being equal, increased intensity usually reflects increased flow turbulence. Thus, a louder murmur is more likely to be pathologic and severe.
1/6: a murmur so soft as to be heard only intermittently and always with concentration and effort. Never immediately
2/6: a murmur that is soft but nonetheless audible immediately and on every beat
3/6: a murmur that is easily audible and relatively loud
4/6: a murmur that is relatively loud and associated with a palpable thrill (always pathologic)
5/6: a murmur loud enough that it can be heard even by placing the edge of the stethoscope’s diaphragm over the patient’s chest
6/6: a murmur so loud that it can be heard even when the stethoscope is not in contact with the chest, but held slightly above its surface
3. What are the causes of a systolic murmur?
Ejection (i.e., increased ‘‘forward’’ flow over the aortic or pulmonic valve): This can be:
○ Physiologic: normal valve, but flow high enough to cause turbulence (anemia, exercise, fever, and other hyperkinetic heart syndromes) ○ Pathologic: abnormal valve, with or without outflow obstruction (i.e., aortic stenosis versus aortic sclerosis) & Regurgitation: ‘‘backward’’ flow from a high- into a low-pressure bed. Although this is usually due to incompetent atrioventricular (AV) valves (mitral/tricuspid), it also can be due to ventricular septal defect.
4. What are functional murmurs?
They are benign findings caused by turbulent ejection into the great vessels. Functional murmurs have no clinical relevance, other than getting into the differential diagnosis of a systolic murmur.
5. What is the most common systolic ejection murmur of the elderly?
The murmur of aortic sclerosis. This early peaking systolic murmur is extremely age related, affecting 21% to 26% of persons older than 65 and 55% to 75% of octogenarians. (Conversely, the prevalence of aortic stenosis in these age groups is 2% and 2.6%, respectively.) The murmur of aortic sclerosis may be due to either a degenerative change of the aortic valve or abnormalities of the aortic root. Senile degeneration of the aortic valve includes thickening, fibrosis, and occasionally calcification. This can stiffen the valve and yet not cause a transvalvular pressure gradient. In fact, commissural fusion is typically absent in aortic sclerosis. Abnormalities of the aortic root may be diffuse (such as a tortuous and dilated aorta) or localized (like a calcific spur or an atherosclerotic plaque that protrudes into the lumen, creating a turbulent bloodstream).
6. How can physical examination help differentiate functional from pathologic murmurs?
There are two golden and three silver rules:
The first golden rule is to always judge (systolic) murmurs like people: by the company they keep. Hence, murmurs that keep bad company (like symptoms; extra sounds; thrill; and abnormal arterial or venous pulse, electrocardiogram [ECG], or chest radiograph) should be considered pathologic until proven otherwise. These murmurs should receive lots of evaluation, including technology based.
The second golden rule is that a diminished or absent S2 usually indicates a poorly moving and abnormal semilunar (aortic or pulmonic) valve. This is the hallmark of pathology. As a flip side, functional systolic murmurs are always accompanied by a well-preserved S2, with normal split.
The three silver rules are:
All holosystolic (or late systolic) murmurs are pathologic.
All diastolic murmurs are pathologic.
All continuous murmurs are pathologic.
Thus, functional murmurs should be systolic, short, soft (typically less than 3/6), early peaking (never passing mid-systole), predominantly circumscribed to the base, and associated with a well-preserved and normally split-second sound. They should have an otherwise normal cardiovascular examination and often disappear with sitting, standing, or straining (as, for example, following a Valsalva maneuver).
7. How much reduction in valvular area is necessary for the aortic stenosis (AS) murmur to become audible?
At least 50% (the minimum for creating a pressure gradient at rest). Mild disease may produce loud murmurs, too, but usually significant hemodynamic compromise (and symptoms) does not occur until a 60% to 70% reduction in valvular area exists. This means that early to mild AS may be subtle at rest. Exercise, however, may intensify the murmur by increasing the output and gradient.
8. What factors may suggest severe aortic stenosis?
Murmur intensity and timing (the louder and later peaking the murmur, the worse the disease)
A single S2
Delayed upstroke/reduced amplitude of the carotid pulse (pulsus parvus and tardus)
9. What is a thrill?
It is a palpable vibratory sensation, often compared to the purring of a cat, and typical of murmurs caused by very high pressure gradients. These, in turn, lead to great turbulence and loudness. Hence, thrills are only present in pathologic murmurs whose intensity is greater than 4/6.
10. What is isometric hand grip, and what does it do to AS and mitral regurgitation (MR) murmurs?
Isometric hand grip is carried out by asking the patient to lock the cupped fingers of both hands into a grip and then trying to pull them apart. The resulting increase in peripheral vascular resistance intensifies MR (and ventricular septal defect) while softening instead AS (and aortic sclerosis). Hence, a positive hand grip argues strongly in favor of MR.
11. What is the Gallavardin phenomenon?
One noticed in some patients with AS, who may exhibit a dissociation of their systolic murmur into two components:
A typical AS-like murmur (medium to low pitched, harsh, right parasternal, typically radiated to the neck, and caused by high-velocity jets into the ascending aorta)
A murmur that instead mimics MR (high pitched, musical, and best heard at the apex) This phenomenon reflects the different transmission of AS: its medium frequencies to the base and its higher frequencies to the apex. The latter may become so prominent as to be misinterpreted as a separate apical ‘‘cooing’’ of MR.
12. Where is the murmur of hypertrophic cardiomyopathy (HCM) best heard?
It depends. When septal hypertrophy obstructs not only left but also right ventricular outflow, the murmur may be louder at the left lower sternal border. More commonly, however, the HCM murmur is louder at the apex. This may often cause a differential diagnosis dilemma with the murmur of MR.
13. What are the characteristics of a ventricular septal defect (VSD) murmur?
VSD murmurs may be holosystolic, crescendo-decrescendo, crescendo, or decrescendo.
A crescendo-decrescendo murmur usually indicates a defect in the muscular part of the septum. Ventricular contraction closes the hole toward the end of systole, thus causing the decrescendo phase of the murmur. Conversely, a defect in the membranous septum will enjoy no systolic reduction in flow and thus produce a murmur that remains constant and holosystolic. VSD murmurs are best heard along the left lower sternal border, often radiating left to right across the chest. VSD murmurs always start immediately after S1.
14. What is a systolic regurgitant murmur?
One characterized by a pressure gradient that causes a retrograde blood flow across an abnormal opening. This can be (1) a ventricular septal defect, (2) an incompetent mitral valve, (3) an incompetent tricuspid valve, or (4) fistulous communication between a high-pressure and a low-pressure vascular bed (such as a patent ductus arteriosus).
15. What are the auscultatory characteristics of systolic regurgitant murmurs?
They tend to start immediately after S1, often extending into S2. They also may have a musical quality, variously described as ‘‘honk’’ or ‘‘whoop.’’ This is usually caused by vibrating vegetations (endocarditis) or chordae tendineae (mitral valve prolapse, dilated cardiomyopathy) and may help separate the more musical murmurs of AV valve regurgitation from the harsher sounds of semilunar stenosis. Note that in contrast to systolic ejection murmurs like AS or VSD, systolic regurgitant murmurs do not increase in intensity after a long diastole.
16. What are the characteristics of the MR murmur?
It is loudest at the apex, radiated to the left axilla or interscapular area, high pitched, plateau, and extending all the way into S2 (holosystolic). S2 is normal in intensity but often widely split. If the gradient is high (and the flow is low), the MR murmur is high pitched. Conversely, if the gradient is low (and the flow is high) the murmur is low pitched. In general, the louder (and longer) the MR murmur, the worse the regurgitation.
17. What are the characteristics of the acute MR murmur?
The acute MR murmur tends to be very short, and even absent, because the left atrium and ventricle often behave like a common chamber, with no pressure gradient between them. Hence, in contrast to that of chronic MR (which is either holosystolic or late systolic), the acute MR murmur is often early systolic (exclusively so in 40% of cases) and is associated with an S4 in 80% of the patients.
18. What are the characteristics of the mitral valve prolapse murmur?
It is a mitral regurgitant murmur—hence, loudest at the apex, mid to late systolic in onset (immediately following the click), and usually extending all the way into the second sound (A2). In fact, it often has a crescendo shape that peaks at S2. It is usually not too loud (never greater than 3/6), with some musical features that have been variously described as whoops or honks (as in the honking of a goose). Indeed, musical murmurs of this kind are almost always due to mitral valve prolapse (MVP).
19. How are diastolic murmurs classified?
By their timing. Hence, the most important division is between murmurs that start just after S2 (i.e., early diastolic—reflecting aortic or pulmonic regurgitation) versus those that start a little later (i.e., mid to late diastolic, often with a presystolic accentuation—reflecting mitral or tricuspid valve stenosis).
20. What is then the best strategy to detect the mitral stenosis (MS) murmur?
The best strategy consists of listening over the apex, with the patient in the left lateral decubitus position, at the end of exhalation, and after a short exercise. Finally, applying the bell with very light pressure also may help. (Strong pressure will instead completely eliminate the low frequencies of MS.)
21. What are the typical auscultatory findings of aortic regurgitation (AR)?
Depending on severity, there may be up to three murmurs (one in systole and two in diastole) plus an ejection click. Of course, the typical auscultatory finding is the diastolic tapering murmur, which, together with the brisk pulse and the enlarged/displaced point of maximal impulse (PMI), constitutes the bedside diagnostic triad of AR. The diastolic tapering murmur is usually best heard over Erb’s point (third or fourth interspace, left parasternal line) but at times also over the aortic area, especially when a tortuous and dilated root pushes the ascending aorta anteriorly and to the right. The decrescendo diastolic murmur of AR is best heard by having the patient sit up and lean forward while holding breath in exhalation. Using the diaphragm and pressing hard on the stethoscope also may help because this murmur is rich in high frequencies. Finally, increasing peripheral vascular resistances (by having the patient squat) will also intensify the murmur. A typical, characteristic early diastolic murmur argues very strongly in favor of the diagnosis of AR.
An accompanying systolic murmur may be due to concomitant AS but most commonly indicates severe regurgitation, followed by an increased systolic flow across the valve. Hence, this accompanying systolic murmur is often referred to as comitans (Latin for ‘‘companion’’). It provides an important clue to the severity of regurgitation. A second diastolic murmur can be due to the rumbling diastolic murmur of Austin Flint (i.e., functional mitral stenosis). The Austin Flint murmur is a mitral stenosis-like diastolic rumble, best heard at the apex, and is due to the regurgitant aortic stream preventing full opening of the anterior mitral leaflet.
22. What is a mammary souffle?
Not a fancy French dish but a systolic-diastolic murmur heard over one or both breasts in late pregnancy and typically disappearing at end of lactation. It is caused by increased flow along the mammary arteries, which explains why its systolic component starts just a little after S1. It can be obliterated by pressing (with finger or stethoscope) over the area of maximal intensity.
